(a) Field of the Invention
The present invention relates to a hub nut fastener for connecting hub nuts to stud bolts formed on a wheel hub of a vehicle during manufacture. More particularly, the present invention relates to a hub nut fastener which can easily undergo pitch conversion to enable the fastening of hub nuts to either a four or five-bolt configuration.
(b) Description of the Related Art
Improvements are continuously being made in the automation of the vehicle manufacturing process to make the process faster and less complicated, and therefore less costly. The mounting of a tire-and-wheel assembly to the vehicle during vehicle manufacture is no exception.
Mounting holes are provided in the wheel, and stud bolts, formed in a wheel hub, are placed through the mounting holes, after which nuts are fastened to the stud bolts to securely mount the tire-and-wheel assembly to the vehicle. In more detail, the mounting holes are formed in the wheel such that a number and an angle thereof correspond to a number and angle of the stud bolts formed on the wheel hub. When mounting the wheel to the wheel hub, the mounting holes are aligned with the stud bolts then the wheel is directed toward the wheel hub such that an inner surface of the wheel is flush with the wheel hub and ends of the stud bolts protrude a predetermined distance from the mounting holes of the wheel. Following this procedure, the nuts are fastened to the stud bolts until the wheel is firmly mounted to the wheel hub of the vehicle.
In the case of small and compact vehicles, the stud bolts are provided on the wheel hub every 90.degree. such that four stud bolts are formed on the wheel hub, whereas with medium and large-size vehicles the stud bolts are provided every 72.degree. on the wheel hub, thereby providing a total of five stud bolts. Accordingly, a corresponding number of mounting holes, at corresponding positions, are formed in the wheel. Such different configurations for dissimilarly sized vehicles are used since larger vehicles receive more stress than do smaller vehicles, and therefore require a more sturdy attachment of the wheels to the wheel hub.
A hub nut fastener for providing a means of securing the nuts to the stud bolts is generally configured to match either the 4-bolt or 5-bolt configuration. This complicates the manufacturing process since both the hub nut fastener for the 4-bolt and the 5-bolt wheel hub must be provided on the assembly line to enable manufacture of all types of vehicles. This lack of uniformity can slow down the manufacturing process and increases overall manufacturing costs as two separate devices are needed.
With reference to FIGS. 8 and 9, there is provided a hub nut fastener enabling application to both the 4 and 5-bolt wheel hub to remedy such problems. Such a nut fastener includes a first, a second, a third, a fourth and a fifth nut runner 1a, 1b, 1c, 1d and 1e initially provided at intervals of 72.degree. to form a circle. Guide holes 2 are provided for the first, third, fourth and fifth nut runners 1a, 1c, 1d and 1e such that the nut runners 1a, 1c, 1d and 1e are able to slide within the guide holes 2 to change position. A direct cylinder 3a is provided at each of the first and third nut runners 1a and 1c, and an indirect cylinder 3b is provided in proximity to the fourth and fifth nut runners 1d and 1e. The indirect cylinder 3b operates a link 4, which, in turn, operates the fourth and fifth nut runners 1d and 1e.
When the cylinders 3a and 3b are in a nonoperating, retracted mode, the nut runners 1a, 1c, 1d and 1e are maintained at equidistant intervals of 72.degree. as described above and as shown in FIG. 8 (the second nut runner 1b is fixed in a single position). However, when the cylinders 3a and 3b operate by extending, the first, third, fourth and fifth nut runners 1a, 1c, 1d and 1e change positions to that shown in FIG. 9. That is, with the operation of the cylinders 3a and 3b, the first, second, third and fourth nut runners 1a, 1b, 1c and 1d are positioned at angles of 90.degree. to form a circle, and the fifth nut runner 1e is positioned away from the circle and is not operated for the fastening of nuts.
However, in the prior hub nut fastener as described above, severe wear occurs in both the link 4 and bolts supporting the cylinders 3a and 3b if the nut fastener is frequently changed from a 4-bolt to a 5-bolt structure. Further, by the positioning of the fifth nut runner 1e away from the circle formed by the remaining nut runners 1a, 1b, 1c and 1d in the case where the hub nut fastener is applied to a 4-bolt wheel hub, damage can occur to the outside surface of the wheel by contact of the fifth nut runner 1e thereon.